Add BepInEx namespace into AssemblyInfo

BepInEx/Properties/AssemblyInfo.cs

@@ -1,6 +1,7 @@
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using BepInEx;
 
 // General Information about an assembly is controlled through the following
 // set of attributes. Change these attribute values to modify the information